Crash Modification Factors for the Flashing Yellow Arrow Treatment at Signalized Intersections
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
This paper presents the results of an evaluation of the flashing yellow arrow (FYA) treatment using data from signalized intersections in Nevada, North Carolina, Oklahoma, and Oregon. The evaluation method was an empirical Bayes beforeafter analysis. The treatments were divided into seven categories depending on the phasing system in the before period (permissive, protectedpermissive, or protected), phasing system in the after period (FYA permissive or FYA protectedpermissive), the number of roads where the FYA was implemented (one road or both roads), and the number of legs at the intersections (three or four). The first five treatment categories involved permissive or protectedpermissive phasing in the before period. Intersections in these five treatment categories experienced a reduction in the primary target crashes under consideration: left turn crashes and left turn with opposing through crashes. The reduction ranged from 15% to 50%, depending on the treatment category. Intersections that had at least one protected left turn phase in the before period and had FYA protectedpermissive left turn phase in the after period experienced an increase in left turn crashes and left turn with opposing through crashes, indicating that replacing a fully protected left turn with FYA will likely cause an increase in left turn crashes.
